Fix cases where delete_records on a has_many association caused errors

because of an ambiguous column name. This happened if the association
model had a default scope that referenced a third table, and the third
table also referenced the original table (with an identical
foreign_key).

Mysql requires that ambiguous columns are deambiguated by using the full
table.column syntax. Postgresql and Sqlite use a different syntax for
updates altogether (and don't tolerate table.name syntax), so the fix
requires always including the full table.column and discarding it later
for Sqlite and Postgresql.

1 files changed, 5 insertions, 0 deletions

diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index 73ffc0de38..93a7a2073c 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -178,6 +178,11 @@ class PostWithDefaultInclude < ActiveRecord::Base
   has_many :comments, :foreign_key => :post_id
 end
 
+class PostWithSpecialCategorization < Post
+  has_many :categorizations, :foreign_key => :post_id
+  default_scope { where(:type => 'PostWithSpecialCategorization').joins(:categorizations).where(:categorizations => { :special => true }) }
+end
+
 class PostWithDefaultScope < ActiveRecord::Base
   self.table_name = 'posts'
   default_scope { order(:title) }